Evaporating unit



June 21, 1932. R. T. SMITH v EyAPoRATING UNIT Filed Feb. 19, 1931 2 Sheets-Sheet 1 INVENTOR 92mm? I 1?! A TTORNEY E Q Q 0 w r s v @QQQQQQQ QQQ June 1932- R. T. SMITH 1,863,933

' EVAPORATING UNIT Filed Feb. 19, 1931 2 sheets-sheet 2 INVENTOR ATTORNEY Panels... 21, 193:

v UNITED memes-we:

RUSSELL '1. SMITH, OF GREENVILLE, IIC' HIGA N, ASBIGNOB '10 GIBSQN BEIRIGEATOB COMPANY, OF GREENVILLE, IICHIGAN, A. CORPORATION OF IICKIQAN c rvaronarmo um Application filed February 18, 1981. Serial No. 516,976.

This invention relates tomefrigerators and more particularly to eva rator units especially adapted for use w1th dry or expansion valve systems.

Refrigerators of the dry or exp nsionvalve system are provided with evapora ors each of which .usually consists of copper tubing sha-ped to form a coil inside which may be disposed the freezing trays. Evaporators so 1 formed are extremely expensive because of the cost of copper and also because ofthe expense involvedi in properly shaping thetubes forming the e aporator. v

Kn refrigerators of the wet or flooded sys- M tem' however, the evaporators are much more simple and economical, comprising a hollowwalled, tray-surrounding shell, the interior of the hollow wall of the shell being in com so munication with the compressor unit. Evapsheet metal, properly, corrugatedfor strengthenin purposes, nd are much more economical t an the continuous copper tube coil evaporator generally used with expansion valve systems. 3

An object of this invention, therefore, is an evaporator for expansion valve systems which is as simple and economical of manufacture as the sheet metal evaporator used with the so-called wet systems. Theevaporator may be formed of sheet metal, and comprises a hollow-walled, tray-surrounding shell having an enlarged portion in which is disposed a coiled copper tube whose inlet is connected to the expansion valve and whose outlet is connected to the suction side of the compressor. The hollow wall is filled with sulphur dioxide which is kept sealed from, but in heat-transferring contact with, the refri crating medium in the coiled copper tube.

- further object is an evaporator comprising a tank,- a hollow-walled, sheet metal, tray-surrounding, U-sha-ped shell whose hollowwall is in communication with the interior of the tank, there being in the lattera coiled copper tube whose inlet and outlet portions are connected t6 the expansion valve and to the com ressor respectively. The hollow wall and t e tank are filled with a heat transferring fluid, such as sulphur dioxide,

orators of this type are generally made :of

and the latter is in intimate contact with the coiled copper tube, the latter being provided with fins b means of which heat transfer between the uidin the tank and the fluid 1n the copper tube is more readily effected, tho these fluids are completely sealed from each other.

Another object is a dry system refrigerator evaporator unit containing two relatively sealed refrigerating mediums, maintained in heat transfering relation with eachother, the primary one of the mediums circulating thru the refrigerator system, that is' the compresv sor, condense'ig and expansion valve and the secondary or'other medium circulating thru the refrigerating compartment or food cabi net. In an evaporator of this type, the .primary medium will absorb heat from the sec-"- .ondary medium, the sealed therefrom, andthe secondary medium will circulate thru the refrigeratlng compartment, absorbing heat therefrom and later surrendering the heat 1 thus absorbed to the primary medium;

Further, in an evaporator of this type; it. is possible to efi'ecteconomical refrigeration by virtue of the fact that the volume of the secondary mediumis rather smallan'd will, of necessity, circulate thru itspart of the evaporator, repeatedly, and at great rate. This is especially true if the surface area of the coil disposed in the body of the sec-" ondary medium is relatively large, as can be readily seen.

Further, the primary system is completely sealed from the secondary system, and accordingly, lubricating oil for thecompressor introduced in the primary system,-w ill returned, to' the compressor, positively, and without its having been lost or dissipated at any point. 9 Another object is a novel process of' refrigeration, one which consists in cooling-a primary medium, presenting the latter to a. small, sealed. body of secondary medium so as to cool the latter, returning'the first'me; 9 dium to heat absorbing mechanical devices such as the compressor and condenser, and circulating the secondary medium thru the refrigerating compartment so as-to absorb heat therefrom. 1

Still further objects are novel forms of evaporators in accordance with the princi ples outlined above. 7

Still further objects will readily occur to those skilled in the art u on reference to the following description an the accompanying drawings in which 1 Fig.1 shows in partial section theevaporator unit of the invention, this fi re being a section asif on the line 1-1 of ig. 2.

Fig. 2 is a rear view of the evaporator.

Referring to the drawin it will be seen that the evaporator inclu es a sheet metal tank 10 having a front cap 12 and a rear cap 15 14. Secured to the tank and su ported thereby is a tray-surrounding, U s aped shell 18 which is formed of an inner plate 20 and an outer plate 22' The lates are connected to each other at their 0 gas by weldin solderso ing, etc. to form a hollow between t e plates, the shell thus being hollow-walled, and the tank is provided with suitable openings 26 by means of which communication between the hollow wall of the shell and the interior aiofthetankisefiectedi p The interior plate 20 is provided with ribs 28 to form supports for the trays which are to be inserted into the eva rator from the front and, is further provi ed with a rib 30,

a0 forming astop to prevent insertion of the trays too far into theevaporator.

Further, the outer plate 22 may be corrugated for stifl'ening purposes, the valleys 36 of the corrugations forming the hollow d th 'dges 38 th 1 te 20 m e n engagmg e P a the tank being closed, and a coiled tube withif dmired, to present surfaces which may welded to one another, if desired. within the tank is a coil of copee eiiiiin having inlet and outlet portions 40 -42 whlch are connected to the expansion valve and to the suction side of the compres-I sor,'not shown, the inlet and outlet ortions being sealedto the rear cap 14 of t e'tank I a 10 at their points of emergence. The .coil 00- cupies a large portion of the volume of the tem, namely, a coinplete separation of theprimaryfluid from all other mediums. The tank. and the shell form a completely sealed circuin shape to surround the trays.

t will also be noted that the volume of the secondary fluid system is not large, and-therefore, boiling or rapid circulation and change of condition can be efiected readily and at a great rate, this efiecting rapid and efiective refrigeration.

Now having described the invention and the preferred embodiment thereof, it is to be understood that the said invention is to be limited, not to the specific details herein set forth, but only by the scope of the claim which follows:

What I claim is In combination, a pair of relatively nested,

- U shaped, sheet metal plates secured and sealed to each other on their U shaped edges, U shaped formations on atleast one of the plates, engaging the other substantially on U lines, to provide U passages between the plates from one] pair of upper edges to the other pair, a cylindrical tank between the upper edges and secured and engaged by the plates thereat on opposed elements of the cylinder, the tank having openings connecting the interior thereof, with the U passages, the ends of in the tank and having an inlet and an outlet projecting thru the tank, the interior of the tube being sealed from the interior of the tank and the space between the plates.

, In testimony whereof, I sign this specification.

RUSSEl' li T. SMITH.

' tank 10 and is further provided with a num ber of fins 44 s aced along the tubing more or e primary may qul p ur on e. The interior df thetank and the hollow wall of the trayereceiving shell is filled wholly or partly, as desired, with a heat transferring I fluid, such asliquid sulphur dioxide, which, as

a secondary. fluid boils and condenses on the coil; and returns by gravity, and circulates thru the tank and shell, absorbing heat from the shell and, therefore, from the trays,and

4 which was up its heat to the copper 'coil d within'thetank. When introducing the secondary fluid into the tank 10 it is preferred to withdraw all the air from the hollow wall shall so that the secondary liquid refrig erant'will operate in a partial vacuum.

It will be noted that the construction is in u dwithanobjective in the drysyse contact with the primary 

